FIX(#2266/#2267): Temporary workaround for cfscrape issues - Anorov/cloudflare-scrape#206

This commit is contained in:
davalanche 2019-05-02 08:43:46 -06:00 committed by evilhero
parent 14c933594b
commit 224c354c99
1 changed files with 71 additions and 15 deletions

View File

@ -2,17 +2,21 @@ import logging
import random
import re
import subprocess
from copy import deepcopy
from time import sleep
import copy
import time
from requests.sessions import Session
from collections import OrderedDict
try:
from urlparse import urlparse
from urlparse import urlunparse
except ImportError:
from urllib.parse import urlparse
from urllib.parse import urlunparse
__version__ = "1.9.5"
__version__ = "1.9.7"
DEFAULT_USER_AGENTS = [
"Mozilla/5.0 (Macintosh; Intel Mac OS X 10_13_2) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/65.0.3325.181 Safari/537.36",
@ -24,8 +28,6 @@ DEFAULT_USER_AGENTS = [
"Mozilla/5.0 (Windows NT 6.3; Win64; x64; rv:57.0) Gecko/20100101 Firefox/57.0"
]
DEFAULT_USER_AGENT = random.choice(DEFAULT_USER_AGENTS)
BUG_REPORT = """\
Cloudflare may have changed their technique, or there may be a bug in the script.
@ -45,12 +47,13 @@ https://github.com/Anorov/cloudflare-scrape/issues\
class CloudflareScraper(Session):
def __init__(self, *args, **kwargs):
self.delay = kwargs.pop("delay", 8)
self.default_delay = 8
self.delay = kwargs.pop("delay", self.default_delay)
super(CloudflareScraper, self).__init__(*args, **kwargs)
if "requests" in self.headers["User-Agent"]:
# Set a random User-Agent if no custom User-Agent has been set
self.headers["User-Agent"] = DEFAULT_USER_AGENT
self.headers["User-Agent"] = random.choice(DEFAULT_USER_AGENTS)
def is_cloudflare_challenge(self, resp):
return (
@ -61,6 +64,19 @@ class CloudflareScraper(Session):
)
def request(self, method, url, *args, **kwargs):
self.headers = (
OrderedDict(
[
('User-Agent', self.headers['User-Agent']),
('Accept', 'text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8'),
('Accept-Language', 'en-US,en;q=0.5'),
('Accept-Encoding', 'gzip, deflate'),
('Connection', 'close'),
('Upgrade-Insecure-Requests', '1')
]
)
)
resp = super(CloudflareScraper, self).request(method, url, *args, **kwargs)
# Check if Cloudflare anti-bot is on
@ -70,22 +86,22 @@ class CloudflareScraper(Session):
return resp
def solve_cf_challenge(self, resp, **original_kwargs):
sleep(self.delay) # Cloudflare requires a delay before solving the challenge
start_time = time.time()
body = resp.text
parsed_url = urlparse(resp.url)
domain = parsed_url.netloc
submit_url = "%s://%s/cdn-cgi/l/chk_jschl" % (parsed_url.scheme, domain)
cloudflare_kwargs = deepcopy(original_kwargs)
cloudflare_kwargs = copy.deepcopy(original_kwargs)
params = cloudflare_kwargs.setdefault("params", {})
headers = cloudflare_kwargs.setdefault("headers", {})
headers["Referer"] = resp.url
try:
params["s"] = re.search(r'name="s"\svalue="(?P<s_value>[^"]+)', body).group('s_value')
params["jschl_vc"] = re.search(r'name="jschl_vc" value="(\w+)"', body).group(1)
params["pass"] = re.search(r'name="pass" value="(.+?)"', body).group(1)
except Exception as e:
# Something is wrong with the page.
# This may indicate Cloudflare has changed their anti-bot
@ -96,16 +112,28 @@ class CloudflareScraper(Session):
# Solve the Javascript challenge
params["jschl_answer"] = self.solve_challenge(body, domain)
# Check if the default delay has been overridden. If not, use the delay required by
# cloudflare.
if self.delay == self.default_delay:
try:
self.delay = float(re.search(r"submit\(\);\r?\n\s*},\s*([0-9]+)", body).group(1)) / float(1000)
except:
pass
# Requests transforms any request into a GET after a redirect,
# so the redirect has to be handled manually here to allow for
# performing other types of requests even as the first request.
method = resp.request.method
cloudflare_kwargs["allow_redirects"] = False
redirect = self.request(method, submit_url, **cloudflare_kwargs)
end_time = time.time()
# Cloudflare requires a delay before solving the challenge
time.sleep(self.delay - (end_time - start_time))
redirect = self.request(method, submit_url, **cloudflare_kwargs)
redirect_location = urlparse(redirect.headers["Location"])
if not redirect_location.netloc:
redirect_url = "%s://%s%s" % (parsed_url.scheme, domain, redirect_location.path)
redirect_url = urlunparse((parsed_url.scheme, domain, redirect_location.path, redirect_location.params, redirect_location.query, redirect_location.fragment))
return self.request(method, redirect_url, **original_kwargs)
return self.request(method, redirect.headers["Location"], **original_kwargs)
@ -116,8 +144,15 @@ class CloudflareScraper(Session):
except Exception:
raise ValueError("Unable to identify Cloudflare IUAM Javascript on website. %s" % BUG_REPORT)
js = re.sub(r"a\.value = (.+ \+ t\.length).+", r"\1", js)
js = re.sub(r"\s{3,}[a-z](?: = |\.).+", "", js).replace("t.length", str(len(domain)))
js = re.sub(r"a\.value = (.+\.toFixed\(10\);).+", r"\1", js)
# Match code that accesses the DOM and remove it, but without stripping too much.
try:
solution_name = re.search("s,t,o,p,b,r,e,a,k,i,n,g,f,\s*(.+)\s*=", js).groups(1)
match = re.search("(.*};)\n\s*(t\s*=(.+))\n\s*(;%s.*)" % (solution_name), js, re.M | re.I | re.DOTALL).groups()
js = match[0] + match[-1]
except Exception:
raise ValueError("Error parsing Cloudflare IUAM Javascript challenge. %s" % BUG_REPORT)
js = js.replace("t.length", str(len(domain)))
# Strip characters that could be used to exit the string context
# These characters are not currently used in Cloudflare's arithmetic snippet
@ -126,9 +161,30 @@ class CloudflareScraper(Session):
if "toFixed" not in js:
raise ValueError("Error parsing Cloudflare IUAM Javascript challenge. %s" % BUG_REPORT)
# 2019-03-20: Cloudflare sometimes stores part of the challenge in a div which is later
# added using document.getElementById(x).innerHTML, so it is necessary to simulate that
# method and value.
try:
# Find the id of the div in the javascript code.
k = re.search(r"k\s+=\s+'([^']+)';", body).group(1)
# Find the div with that id and store its content.
val = re.search(r'<div(.*)id="%s"(.*)>(.*)</div>' % (k), body).group(3)
except Exception:
# If not available, either the code has been modified again, or the old
# style challenge is used.
k = ''
val = ''
# Use vm.runInNewContext to safely evaluate code
# The sandboxed code cannot use the Node.js standard library
js = "console.log(require('vm').runInNewContext('%s', Object.create(null), {timeout: 5000}));" % js
# Add the atob method which is now used by Cloudflares code, but is not available in all node versions.
simulate_document_js = 'var document= {getElementById: function(x) { return {innerHTML:"%s"};}}' % (val)
atob_js = 'var atob = function(str) {return Buffer.from(str, "base64").toString("binary");}'
# t is not defined, so we have to define it and set it to the domain name.
js = '%s;%s;var t="%s";%s' % (simulate_document_js,atob_js,domain,js)
buffer_js = "var Buffer = require('buffer').Buffer"
# Pass Buffer into the new context, so it is available for atob.
js = "%s;console.log(require('vm').runInNewContext('%s', {'Buffer':Buffer,'g':String.fromCharCode}, {timeout: 5000}));" % (buffer_js, js)
try:
result = subprocess.check_output(["node", "-e", js]).strip()